Concrete spreading apparatus



April 13, 1965 w. A. RETZLAFF ETAL 3,177,784

CONCRETE SPREADING APPARATUS 6 Sheets-Sheet 1 Filed Sept. 15. 1961 www lllllllnllil 111ml. Fitz/i 67m my WMXJZZ April 13, 1965 W. A. RETZLAFF ETAL CONCRETE SPREADING APPARATUS Filed Sept. 15, 1961 6 Sheets-Sheet 2 April 13, 1965 w. A. RETZLAFF ETAL 7 CONCRETE SPREADING APPARATUS 6 Sheets-Sheet 3 Filed Sept. 15, 1961 3mm WzZ/zazzz AFpfz/aff 67m Way WMaxozz [an my 214mm April 1965 w. A. RETZLAFF ETAL 3,177,784

CONCRETE SPREADING APPARATUS Filed Sept. 15. 1961 6 Sheets-Sheet 4 .MH HIJIHIH Q 9 3 Q? Q i g ullllm 1:;

6 Sheets-Sheet 5 Iill-I IIIIL VII II I l I '5? Iii/him AJZpiz/a/f IK M2 202: [17m my MEL? W. A. RETZLAFF ETAL CONCRETE SPREADING APPARATUS an J5:

[17in Wi April 13, 1965 Filed Sept. 15. 1961 April 1965 w. A. RETZLAFF ETAL 3,177,784

CONCRETE SPREADING APPARATUS 3,177,784 CONCRETE SPREADING APPARATUS William A. Retzlafi, Wauwatosa, Wis, Glenway W. Maxon, Shorewood, Wis., and Gleuway Maxon, Jr., 1943 N summit Ave., Milwaukee, Wis; said Retzlaif and said Glenway W. Maxon assiguors to said Glenway Maxon, .Jr. Filed Sept. 15, 1961, Ser. No. 138,376

Claims. (Cl. 94-39) This invention relates generally to the art of paving roadways with concrete, and it has more particular reference to improvements in apparatus for placing and spreading concrete upon roadways, such as highways, airport runways, parking areas and the like. I In general, it is the object of this invention to provide apparatus for use .in the construction of roadways, such as highway strips, airport runways and the like, which greatly facilitates the placement of concrete upon the roadway or subgrade and makes possible the paving of concrete roadways in a much shorter time than was possible heretofore.

More specifically, this invention has as its objective the provision of apparatus which greatly facilitates the placement upon a subgrade of concrete delivered to the apparatus in an already mixed condition, and this, of course, is in distinction to the well known types of pavers that have been used heretofore to mix concrete at the site at which it is to be placed, which had a boom that carried a bucket or the like over the roadway for distribution of the concrete upon the subgrade.

The objectives of this invention are realized through the provision of a main self-propelled vehicle which may be considered a power, and control unit and whichhas a hopper thereon to receive concrete from a transit truck or the like while the vehicle is either operating directly on the subgrade, or on the shoulder alongside the subgrade, or is supported for travel along the subgrade upon the forms which extend along the sides thereof to define the width of the pavement to be laid This main vehicle is provided with an elongated conveyor that is pivoted to the vehicle at its front end so that the rear portion of the conveyor is swingable from side to side across the subgrade at a' substantial distance behind the main vehicle, While the forward end of the conveyor is always in a position to receive concrete from the feed hopper on the main vehicle. Thus concrete dumped into the feed hopper from a transit truck or the like is conducted rearwardly by the conveyor for discharge onto the subgrade at a substantial distance behind the main vehicle. H

According to this invention, the main vehicle may be provided with a chassis mounted upon endless treads, and it has an engine by which it can be driven on and along thesubgrade with sufiicient power so that it can pull a planer behind it, coupled closely adjacent to it. The planer, of course, imparts a final smooth surface to the subgrade upon which concrete is to be distributed.

A highly important aspect of the invention, and one that is in large part accountable for its success, resides in the provision of a second or trailing vehicle, adapted to be coupled to the main vehicle and to be supported for travel over the subgrade, along its length, a distance behind the main vehicle, and which trailing vehicle has means thereon for supporting a rear portion of the elongated conveyor without interfering with side to side swinging motion of said rear portion of the conveyor.

r The-objectives of this invention are most satisfactorily realized when the trailing vehicle is self propelled and haswheels at its opposite sides that span the subgrade and either ride upon the ground along each margin of the subgrade or else track directly upon the forms which define the width of thesubgrade, and when the trailing veice hicle is provided with a trough-like structure on its rear that is long enough'to extend across the entire width of the subgrade, said trough-like structure being open at its top and bottom to receive concrete discharging from the rear end of the conveyor and to distribute the same along the subgrade as the trailing vehicle advances thereover.

Other advantages of this invention are achieved by pro,

viding the trough-like structure on the trailing vehicle with a strike-olf along its rear, having a lower edge which is adapted to define the upper surface of the concrete dis tributed along the subgrade from the trough. i I

Still further advantages are achieved by the apparatus of this invention as a result of incorporation in the trailing unit of transversely elongated supporting rods orflthe' like which extend entirely across the subgrade and which are located to pick up wirereinforcing matting that is laid on the subgrade ahead of the trailing unit. These rods support the matting at a predetermined elevation beneath the lower edge of the strike-01f while concrete is being distributed onto the subgrade from the trough, and they thus assure correct placement of the matting in the concrete strip laid down by the apparatus of this invention.

With these and other objects in view which Will appear as the description proceeds, this invention resides'in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims. I a p The accompanying drawings illustrate several complete examples ofthe physical embodiments of the invention; constructed according to the best modes so far devised for the practical application of the principles thereof, andin which: l i

FIGURE 1 is a plan View of concrete spreading apparatus embodying this invention, showing the same as comprised of main and trailing vehicles and in use upon aroadway; i i FIGURE 2 is a side elevationalview of the apparatus seen in FIGURE 1, portions thereof 'beihg broken away and shown in section; H i I FIGURE 3 is amore or less diagrammatic plan view illustrating the operation of the apparatus shown in.

FIGURE 6a is a detail sectional view taken on the line FIGURE 7 is a plan view of a modified embodiment of the apparatus of this invention; and j FIGURE 8 is a side elevational view of the apparatus shown in FIGURE i in section.

Referring now more particularlyt'o theiaccompahying drawings, in which like reference characters'havebeen.

appliedto like parts :throughout'the views, the invention in its preferredforrn is more or less diagrammatically I illustrated in FIGURES "1 and 2. As therein seen,the' apparatus of this invention comprises a self propelled main vehicle 10, a self propelled trailing vehicle 11, and an elongated conveyor 12 carried by the main vehicle,

extending lengthwise. between the main and trailing hicles, and jointly supported thereby. In general it is the purpose of the apparatus shown in FIGURES 1 and 2 to facilitate the spreading of concrete on a subgrade, indicated at 14, between parallel spaced 7,with parts broken away and shown apart jcorlventional forms which define the width of concrete paving to be laid ,on the subgrade. For this purpose, both the main and trailing vehicles have transversely elongated chassis which are adapted to span the entire width of the subgrade, and which are supported by wheels or the like for travel lengthwise along the s ubgrade. In the present case the main vehicle 10 has a chassis 17 which at each side thereof carries a pair of wheels 18 of the double flanged type that are adapted to ride directly upon, and be guided by, the tops of the conventional forms 15. To assure the best possible traction upon the forms, the wheels 18 preferably have rubber treads, such as seen best at 19 in FIGURE 5. Alternately, rubber tired wheels on the chassis may support the main vehicle by engagement with the ground outside the subgrade in instances where forms are not placed a distance ahead of the location at which concrete is deposited upon the subgrade.

The trailing vehicle 11 is likewise provided with a chassis 20 which is wide enough to span the subgrade, and this chassis likewise carries either rubber tired wheels adapted to ride upon the ground outside the subgrade, or flanger rubber treaded wheels 21 such as have been shown at each side of the chassis and ride directly upon the forms 15. In this case, however, the chassis 20 carries three wheels at each side thereof, adapted to engage the tops of the forms at locations spaced lengthwise therealong. The two forward wheels at each side of the trailing vehicle chassis are double flanged, to be guided by the forms 15, while the rear wheels 22 have flanges only at their outer sides so as not to disturb freshly poured concrete adjacent to the forms.

The main vehicle 10 can be considered a power and control unit since it has an internal combustion engine 23 mounted on its chassis to drive a series of pumps indicated at 24. A seat 25 for an operator is preferably located at a control station which is at the left hand side of the main vehicle, looking in the direction of travel of the apparatus along the subgrade, which direction is indicated by the arrow in FIGURE 1. Control valves 26 at the control station enable theoperator to control the transmission of hydraulic fluid from the pumps to hydraulic motors 27 which may be drivingly connected with wheels '18 at each side of the main vehicle, and also toga double acting conveyor swing cylinder 28. Similarly, the control valves'govern the supply of hydraulic'flnid to hydraulic =m0tors 29 drivingly connected to wheels 21 at e'ach:side'of the trailing vehicle. Such fluid as is transmitted to the motors 29 is carried through transmission lines, indicatedrgenerally at 30, that extendrearWaIdIY fromthe control valves along one side of the frame 31 of the conveyor 12. Each-trans mission iliney includes ;a. rigid 'upright" duct 32 that extends upwardly from the frame of the conveyor, 5a

similar mast-like duct 33 on the chassisof the trailing vehicle, and a length of flexible duct or hose 30 that connectsthe upright-ducts.' The masts-32 and 33 provide for sufiicient slack in the length of the flexible transmission lines '30extendingwtherebetween to permit a substantial degree of swinging motion of .the conveyor from side-to'side in a manner; now about to be described.

Thefframefll of the conveyor '12 is supported at its front endupon the chassis 17 of the main vehicle 10 by meansof -a;.pivotal connection 35, :with the-forward end of the eonveyorlocated at the side of the chassis reinote from ithe control station and the :operators seat 25. Pivot35 is arranged on a :vertical axis so that the rear portion :of the conveyor can swing from side to side over the subgrade across its entire width. As indicated,'the-conveyor 12 comprises an endless belt 36 constrained to,-travel about a drive roller 37 at the rear end of 'the aconveyor-frame 31 and anidler roller 38 atthe front end of theconve'yor frame; The belt, of c.oi1rse,;is'driven-insucha direction by the drive roller 37 "that its'upper stretch will travel rearwardly, so

1 is movable that concrete deposited in a feed hopper 40 carried by the front end portion of the frame, over the top stretch of the belt 36, will be conducted rearwardly along the length of the conveyor for discharge from its rear extremity. The drive roller 37 at the rear end of the conveyor frame is driven from the hydraulic motor 44 under the control of the valves 26 at the operators station. I

The upper stretch of the belt, between the front and rear rollers 37 and 38, is supported at each side thereof by sets of cooperating rollers 42 comprising a center roller that rotates on a horizontal axis, and opposite downwardly and laterally inwardly inclined side rollers which allow the upper stretch of the belt to take on the shape of a well defined trough in which concrete is confined as it is conducted rearwardly along the conveyor. These rollers are supported by the frame 31 of the conveyor by means which includes bearing members 43 fixedto the inner sides of the opposite longitudinal members that comprise the frame 31 of the conveyor. The bearing members 43, of course, have upper portions that provide trunnions for the upper ends of the rollers.

At zones adjacent to each end of the conveyor, the axes of the side rollers are tilted less and finally reach horizontal at the extremities ofthe conveyor.

The double acting hydraulic cylinder 28 by which the conveyor is swung from side to side has one end pivotally connected 'to the trailing portion of the chassis of the main vehicle, as at 46, and the piston rod 48 projecting from its other end is pivotally connected as at 47 withthe inner'side of the conveyor frame 31, Consequently, in the osition of the conveyor indicated in solid lines in FIGURES 1 and 3, wherein it extends straight'back along the subgrade parallel to and near the adjacent form 15, retraction of the piston rod 48 of the cylinder will cause the conveyor to be swung inwardly over the subgrade towardthe position indicated by broken lines in FIGURE/3, from which position it can be returned by effecting extension of the piston rod 48.

The chassis 20 of the trailing vehicle 11 comprises a transversely elongated horizontal lower framework 50, and an upper bridging structure 51 extending over the forward portion of the chassis, ahead of its center wheels 21. The bridging structure. 51 comprises opposite up right rigid legs 52 which extend upwardly from the front corners of the lower framework 50, behind the front wheels 21 of the chassis, opposite upright rigid rear legs 53 which extend upwardly from the sides of the lower framework at locations slightly forwardly of the center wheels of the chassis, and front and rear elongated transverse beams 54 which respectively join the upper ends of the front and rear legs 52 and 53. The rear portion of the conveyor 12 extends through the chassis of the trailing vehicle, at alevel above the lower framework 50 but beneath the transverse beams 54 of the bridging structure 51, as seen best in FIGURE 2. Transversely elongated horizontal rails 55 are aflixed to the'inner sides. of the beams 54, to guidingly support a. dolly, generally desig nated 56, from which the rear portion of the conveyor is suspended. The dolly comprises a rectangular frame structure 57 having r'ollers -58at its four corners'that ride upon the rails 55, and hence the dolly is constrained to motion, from side to'side of the trailing vehicle. Diagonal braces 63 extend from corner to corner of the dolly frame, intersecting at thecenter thereof. I

The rear portion of the conveyor is supported from the dolly 56 bymeans of an inverted U-shaped frame 60 having opposite depending legs 6'1 that straddle and support the conveyor frame, and a bightpo'rtion '62 which passes over the top'of the conveyor and which is connected to the diagonal braces 63 on the dolly by means of a pivot pin '64 that extends downwardly from the intersection of the braces. The pin 64 is, of course, disposed on a vertical axis which is fixed with'respect to the dolly but which with the dolly transversely across the subgrade upon the chassis of'the trailing vehicle, and hencethe dolly moves across the trailing vehicle chassis in unison with swinging motion of the conveyor.

The lower ends of the legs 61 of the inverted U-shaped member are pivotally connected with the opposite side members 31 of the conveyor frame by means of a horizontal transverse shaft 65, which allows the conveyor to have up and down pivotal motion relative to the chassis of the trailing vehicle.

It will be apparent that the dolly so supports the conveyor from the trailing vehicle as to allow the conveyor to swing from side to side across the subgrade without interference from the trailing vehicle. Such swinging movement of the conveyor, of course, tends to impart either forward or rearward forces to the dolly, depending upon the direction the conveyor is swung; and to insure that such forces will not result in binding of the dolly on its rails 55, the dolly is preferably provided with a series of edge rollers 67 at its four corners, which rotate on vertical axes and engage the inner sides of the rails 55.

If desired, the operator of the apparatus can take advantage of the fore-and-aft forces exerted upon the main and trailing vehicles through their connections with the conveyor, to effect alternate advancing motion of thevehicles along the subgrade in consequence of back and forth swinging movement of the conveyor across the subgrade. For example, the wheels of the trailing vehicle may be locked against rotation during the time the conveyor is swung toward its position indicated insolid lines to facilitate forward propulsion of the main vehicle by its wheels, and conversely, the Wheels of the main vehicle may be locked against rotation during times when the conveyor is swung away from its position shown in solid lines to facilitate forward travel of the trailing vehicle. In the first instance, the main vehicle is more or less pushed forward away from the anchored trailing vehicle by the conveyor as the conveyor is swung toward its position parallel with the subgrade, and in the latter instance, the conveyor pulls the trailing vehicle forwardly toward the anchored main vehicle during swinging of the conveyor across the subgrade. In this way, of course, the frame 31 of the conveyor provides a link of fixed length joining the vehicles, to enable them to be alternately advanced.

A highly important feature of the apparatus described is that concrete discharges from the rear of the conveyor into a transversely elongated trough 69 on the rear of the trailing unit. If the vehicles are alternately advanced as described, the trough will be loaded with concrete at times when the trailing vehicle is stationary, and it will spread concrete upon the subgrade at times when the trailing unit is advanced relative to the main vehicle.

This trough extends entirely across the subgrade, is open at its top and bottom, has an upright relatively low front wall 70 which extends beneath the rear extremity of the conveyor, and a higher upright rear wall 71 spaced a distance behind the extremity of the conveyor. The opposite ends of these trough walls, of course, are spanned by panels 72 which close the ends of the trough and lie closely adjacent to the forms 15.

The trough is mounted on the chassis of the trailing vehicle behind the rear posts 53 of the bridging structure thereof, and occupies a position substantially between the rearmost pairs of wheels. of the trailing vehicle. Itsbottom is located at a level which is but slightly above the tops of the forms 15, and preferably it has astrike-off 73 secured to its rear Wall 71 for a degree of up and down adjusting motion relative to the bottom of the trough. The strike-off extends entirely across the rear of the trough, slightly beyond its sides and over the tops of the forms 15, and it is ordinarily adjusted so that its lower edge 74 is located in a plane only a slight distance above the tops of the forms so that it will level off and define the surface of concrete deposited upon the subgrade by the trough.

With the position of the trough as described, concrete 'to the chassis Ztl of the trailing vehicle, to discharge into the trough 69. Since the conveyor can be swung back and forth across the subgrade, concrete can be distributed throughout the entire length of the trough, so that it will discharge more or less uniformly on the subgrade and be leveled off by the strike-off 7 3.

A mirror M can be mounted on the frame 31 of the con veyor, above and behind the rear end of the belt, so that the operator can watch the loading of the trough and the deposit of concrete therefrom onto the subgrade.

The conveyor has a high capacity, preferably on the order of 8 yards of concrete per 32 second interval. Hence, a skilled operator properly coordinating the alternate advance of the main and trailing vehicles with swinging of the conveyor can distribute or spread as much as 8 yards of concrete onto the subgrade every 32 seconds,

across its entire width which may be on the order of 24.

ft. wide, and to the usual depth of 9 inches.

It is understood, of course, that finishing machines or workers on a finishing trestle may impart the final substantially smooth surface to the concrete from a location rearwardly of the trailing vehicle.

Still another feature of the apparatus illustrated in FIGURES 1 and 2 is that the trailing vehicle is provided with means to pick up reinforcing wire matting 75 that is laid on the subgrade and to support such matting at a predetermined distance beneath the finished grade of the concrete laid on the subgrade, depending upon specifications. For a roadway that is to have concrete laid thereon to a depth of 9 inches, for example, the matting is ordinarily located at a depth of about 3 inches below the finished grade. Such matting can be initially laid on the subgrade in the area between the main and trailing vehicles, by workmen handling relatively short lengths of the matting, or it can be unrolled onto the subgrade from a supply truck driven forwardly along the subgrade ahead of the main vehicle.

The means for picking up this matting and supporting it at a predetermined distance above the subgrade comprises a plurality of horizontal rods or bars 77, 78 and 79 carried by the trailing vehicle and extending entirely across the subgrade between the forms 15. As shown in FIGURES 2 and 4, there are three such rods, all at the same level, and in the nature of substantially fiat triangular cross section bars which have their ends connected under tension to the lower framework 50 of the trailing These bars are mountedwith their bases hori- The forward ing vehicle, a short distance ahead of the trough 69. These bars are so located that their apexes are approximately three inches beneath the lower edge 73 of the strike-off on the trough when the bars are in their operative positions shown.

In the construction of concrete roadways and the like,

it is common practice to employ bulkheads which extend transversely across the sub-grade and are placed thereon at regular intervals along its length. The wire mesh re-..

inforcing matting, in most cases, is interrupted ateach of these bulkheads. V

Since the bulkheads extend upwardly to the plane of the tops of the forms,.they lie directly in the path along which the bars 77, 78 and 79 travel during use of the apparatus. Hence, it is a feature of the apparatus. of this invention that each of the bars 77, 78 ,and179. may be lifted upwardly to clear the bulkheads as they reach pos1tions closely adjacent thereto. After the bars have passed over the bulkheads, they may again be moved downwardly to their normal operating positions shown;

The means for so mounting the bars for up and down motion relative to the trailing vehicle is best seen in FIGURE 6a, and comprises outboard brackets 80 fixed to the side beams 81 of the lower framework 50 on the trailing unit, at locations adjacent to the opposite ends of each bar 77, 78 and 79. The brackets are substantially channel shaped, each having an upright web 82 that 'flatwise faces the outer side of its beam 81 but is spaced a distance outwardly therefrom, and spaced apart flanges 83 which extend inwardly to and are fixed to the adjacent beam 81 as by Welding or the like.

Each bracket is provided with a bar tensioning and supporting member 84, which occupies an upright position in the space between the web of the bracket and the adjacent beam 81 of the trailing vehicle, and between the flanges 83 of the bracket to be guided by the latter for lengthwise up and down motion relative to the trailing vehicle. Such up and down motion is imparted to the bar supporting member 84 by a manually actuatable lever 85 connected to the upper portion of the bracket by a pivot pin 86 that has its ends received in the flanges 83 of the bracket, to provide for swinging motion of the lever about an axis that is parallel to and slightly above the adjacent longitudinal beam 81, to and from a normal position extending horizontally outwardly from its pivot and resting upon the top of the web of the bracket. A link 87 having its opposite ends pivotally connected to the upper portion of the bar supporting mernber 84 and to the lever by pivot pins 88 provides a motion transmitting connection between the lever and the bar supporting member by which the latter is moved endwise upwardly in consequence of swinging of the lever upwardly and inwardly to the broken line position seen in FIGURE 6a, a distance somewhat greater than the depth of the bars 77, 78 and 79 beneath the lower edge 74 of the strike-off.

The bar supporting members 84 normally project downwardly to have their lower end portions disposed just inside the forms 15, below their tops, and adjacent to the Opposite ends of each of the bars 77, 78 and 79, to which they'are welded or otherwise secured. Hence, each of the bars in turn may be readily moved upwardly to a position above the tops of the forms 15 to enable the bar to pass over a bulkhead as it nears the same, merely by swinging the levers 85 for its two supporting members upwardly and inwardly about their pivots 86. After the bars pass the bulkheads, of course, the levers 85 for each are swung down to their normal positions defined by their engagement with the webs of the brackets, and workmen at the site can easily thread the ends of the matting 75 over the leading bar 77 as soon as it is lowered to its normal level.

It is a feature of the invention that the bar supporting members 84. are also employed to maintain substantial tension on the bars connected thereto and carried thereby. As seen in FIGURE 6a, each bar supporting member is mounted for tilting motion about a fulcrum provided by a roller 89. The periphery of the roller is at all times held engaged with the inner face 90 of the bar supportingrnember, at a location intermediate the ends of the latter, by a wear plate 91 on the bracket, having a flange 92 which extends outwardly toward the lower portion of the bar supporting member and, under the roller 89. Hence tilting of the bar supporting member about the fulcrum'89 to move its lower end portion outwardly toward the adjacent form 15 applies tensioning force to the bar connected therewith. Tension is relieved by tilting the member 84 in the opposite direction.

The tension on each bar is adjustably maintained by means which acts upon the upper end portion of the bar supporting member, and which comprises an angle shaped pressure plate 93 having an upright flange 94 fiatwise overlying the outer face 95 of the bar and holding the periphery of a roller 96 in engagement therewith. A lower flange 97 'on the plate extends under the roller 96 to hold it in place. A pair of upper and lower cap screws 98 threaded in bosses 99 on the web 82 of the bracket and having their inner ends seated in wells 100 in the outer side of the wear plate provide for adjustment of the pressure which can be exerted upon the upper end of the bar supporting member 85 through the roller 95, tending to tilt the member about its fulcrum 89. The lower screw is located substantially at the level of the roller 96, and the extremity of the upper screw in effect provides a fulcrum about which the pressure plate may be tilted to cause forces of diiferent magnitudes to be applied to the upper end of the bar supporting member by the lower screw.

The rollers 89 and 96, of course, enable the bar supporting members to be shifted upwardly and downwardly while at the same time assuring that the bars 77, 78 and 79 will be at the proper tension whenever they are lowered to their normal operating positions.

It will be appreciated, of course, that the means for adjusting the tension on the bars, described above, need not necessarily be incorporated in the brackets 80 at both sides of the trailing vehicle.

When the apparatus is in use, workmen at the site lay the matting in side by side longitudinally extending strips, spaced apart slightly along the center of the subgrade and between the bulkheads (not shown) that are placed across the subgrade at uniform intervals along its length. These workmen then thread the ends of the matting over the leading bars 77 when the apparatus is first started, and again at each bulkhead. Thereafter, the matting is automatically picked up by the bars and held at the desired level to be embedded in the concrete being deposited by the apparatus as it advances along the subgrade.

Attention is directed to the fact that the two rearmost bars 78 and 79 are respectively located just forward of the trough and just aft of it, and are thus so positioned as to support the matting during the time concrete flows downwardly out of the trough into the roadbed or subgrade. Ordinarily the concrete falling down out of the trough tends to press the matting downwardly by its weight, to a level below that of the rear bar 79. For this reason, and also because the rear bar must travel through the concrete deposited upon the subgrade, the substantial- 1y thin wedge-like shape of the bar is most advantageous.

It is particularly important that its upper surface slope gently downwardly toward the leading edge of the bar, to enable it to slide smoothly under the matting and to also enable the bar to slice cleanly through the concrete, whereby the concrete will readily flow around it without leaving objectionable voids therein.

The bars 77, 78 and 79 are also mounted from the chassis of the trailing vehicle so as to prevent sagging of their medial portions. For this purpose a spindle 102 is fixed to the center of each bar and projects upwardly therefrom. The spindles on the two forward bars 77 and 78 have their upper ends passing through holes in the undersides of the two box-section transverse members 103 of the lower framework, and heads thereon prevent the medial portions of bars 77 and 78 from sagging beneath the desired level without interfering with upward motion of the bars to their inoperative positions above the tops of the forms. The spindle on the rear bar 79 is flattened as shown to more easily pass edgewise through the concrete, and projects upwardly therefrom through a hole in the rear box-section transverse beam 103 on the framework 50, to the interior thereof, as best seen in FIGURE 6 This last designated spindle is endwise joined to a piston-like member 104 inside the rear beam, that has a flange 105 on its upper end to slidingly fit the interior of the beam. A downwardly facing shoulder 186 on the piston-like member engages the b0ttom-wall of the beam to prevent downward motion'of the spindle and hold the medial portion of the bar 79 at the same elevation as its ends.

A coil spring 107 encircling the piston-like member 104 and confined between its flange 105 and the bottom wall of the beam assists in raising the bar when it is lifted over the bulkheads in the subgrade. It will be understood, of course, that this center support for the rear bar 79 is rigid enough to prevent the bar from bowing rearwardly as it plows through the concrete deposited upon the subgrade from the trough. i

With the apparatus described, transit trucks containing freshly mixed concrete from a central mixing plant can deliver loads of concrete to themain vehicle, discharging it into the feed hopper 46 at the front of the belt conveyor. While thus discharging its load, the transit truck occupies a location alongside the subgrade, remote from the operator at the control. station, so that the operator can observe the discharge of concrete from the transit truck into the feed hopper, and so that the driver of the transit truck can also watch the operator of the main vehicle and receive instruction signals from him to assure the proper discharge of the load carried by the transit truck.

A somewhat more versatile form of the apparatus of this invention is diagrammatically disclosed in FIGURES 7 and 8. As therein shown, the main vehicle 10', which likewise comprises a power and control unit, has a chassis 103 that is mounted upon endless treads 109, and it may operate directly upon the subgrade or be run alongside the same, since it does not depend for support upon the forms at the sides of the subgrade. The vehicle 10' is powerful enough to enable the vehicle to pull a planer 116 of a conventional type, with the planer close coupled to the rear of the chassis of the main vehicle by draft bars 111 or the like. The main vehicle 10 in this case, must travel on and along the subgrade so that the planer 110 which follows it will impart to the subgrade the desired smooth surface upon which the concrete is to be distributed.

The main vehicle 16 carries an elongated conveyor 12' that extends rearwardly from the main vehicle, Where its forward end is supported from the chassis for pivotal motion about a vertical axis diagrammatically indicated at 113, located medially between the treads 109 and near their forwawrd ends. In this case, the forward end portion of the conveyor frame 114, which may carry the feed hopper is mounted on a turntable 115 carried by the chassis 108 for turning movement about the axis 113. Rollers 117, carried by the side members of the conveyor frame 31' at their undersides, ride upon a track 118 thereunder on the rear of the vehicle chassis, and this track is curved so as to be concentric to the axis 113 and thus provide exceptionally good support for the conveyor throughout its entire range of swinging movement across the subgrade.

It will be appreciated, of course, that the means just described is capable of adequately supporting the conveyor in cantilever fashion, without reliance upon a trailing vehicle such as is used with the vehicle 10 of the first described embodiment of the invention. In that case the conveyor would discharge directly upon the subgrade at a substantial distance rearwardly from the main vehicle.

If desired, however, the rear portion of the conveyor can be supported for movement transversely across the width of the subgrade on a dolly carried by a trailing vehicle such as described previously.

The main vehicle 10', being mounted on endless treads, is capable of travel outside of the subgrade but along one margin thereof in states which prohibit any vehicle from operating directly upon the subgrade. In such cases, of course, the conveyor 12 of the main vehicle can have its rear supported upon a trailing vehicle such-as that shown in FIGURES 1' to 3, without interfering with swinging motion from side to side of the subgrade. The trailing vehicle, of course, could etiher be self propelled or draft coupled with the main vehicle by its pivotal con nection with the rear of the conveyor. If the trailing vehicle is pulled by the main vehicle 10', it need not be to self propelled and the hydraulic motors for its wheels could be eliminated.

The endless tread mounted main vehicle 10' is also exceptionally useful for distributing. concrete along the tightly curved approaches to cloverleaf intersections of superhighways or the like, where it would travel directly on the subgrade. In such work it is impracticable to operate a vehicle upon the curving forms of such approaches, and there is not enough room at the shoulder for a vehicle to run alongside the subgrade. If space at the shoulder is sulficient, the main vehicle can, of course, operate on the shoulder with its cantilever mounted conveyor extending out over the subgrade to discharge directly thereon.

One of the features of the main vehicle disclosed in FIGURES 7 and 8 is that its chassis may have a pair of transversely extending idler rollers mounted thereon at its front, for engagement with the rear wheels of a transit truck (not shown) to thus enable the main vehicle to push the transit truck along ahead of it during the time the transit truck is discharging its contents into the feed hopper 40 at the front of the conveyor. This has the advantage of enabling the operator of the main vehicle 10' to control the advance of the transit truck by and from the main vehicle 10.

From the foregoing description taken together with the accompanying drawings, it will be apparent that this in vention provides highly versatile apparatus for use in the construction of concrete paved roadways, such as highways, airport runways, parking areas and the like, by which the placement of concrete on the subgrade is greatly facilitated, and which makes possible the paving of concrete roadways in a much shorter time than was heretofore possible.

What is claimed as our invention is:

1. Apparatus for placing concrete upon a subgrade, comprising: a first vehicle adapted for travel along the subgrade; a second vehicle adapted for travel along the subgrade in spaced trailing relation to the first vehicle, and having. an elongated chassis to transversely span the subgrade; an elongated conveyor having a rigid frame extending lengthwise between said vehicles, for conducting concrete rearwardly from the first vehicle and discharging it at a location adjacent to the second vehicle, said frame providing a link of fixed. length; means con necting the front of the conveyor frame to the first vehicle and supporting the conveyor for pivotal motion about an upright axis fixed with respectto the first vehicle, to provide for swinging movement of the rear portion of the conveyor across the subgrade, toward and from a position at which the conveyor is substantially normal to thelength of the chassis of the second vehicle; means connecting a rear portion of the conveyor frame with the second vehicle, comprising a part on the frame fixed against relative movement lengthwise thereof and which moves back and forth with the conveyor, relative to the second vehicle, and means on the second vehicle coopcrating with saidconveyor part to constrain the same to movement substantially lengthwise of the chassis of the second vehicle, as the conveyor swings back and forth across the subgrade; and power means'on one of said vehicles operatively connected with the conveyor frame to impart back and forth swinging motion thereto, said power means cooperating with the link provided by the conveyor frame and said means connecting it with the vehicles when thefirst vehicle is held against movement to effect movement of the second vehicle toward the first .vehicle in consequence of swinging of the conveyor frame away from said position substantially normal to the chassis of the second vehicle, and cooperating with the link 7 provided by the conveyor frame and said means connecting it with the vehicles when the second vehicle is held against movement to effect movement of the first vehicle 2'. In apparatus for placing concrete upon a subgrade: spaced apart leading and trailing vehicles adapted to span and travel along the subgrade; an elongated conveyor having a frame extending lengthwise between said vehicles, for conducting concrete rearwardly from the first vehicle and discharging it onto the subgrade at a location adjacent to the trailing vehicle, said frame providing a link of fixed length; means suppor'tingly connecting the front portion of the conveyor frame to the leading vehicle for pivotal motion of the conveyor about an upright axis fixed with respect to the leading vehicle, so as to provide for swinging the conveyor back and forth across the subgrade, toward and from a position at which the conveyor is in endwise alignment with the subgrade; means on the trailing vehicle supporting the rear portion of the conveyor frame for back and forth swinging movement of the conveyor relative to the trailing vehicle; power means on one of said vehicles operatively connected with the conveyor frame for imparting back and forth swinging movement thereto; and means cooperating with the link provided by the conveyor frame to provide for translation of forces which said power means imposes thereon to swing the conveyor back and forth across the subgrade into forces on said vehicles that can be utilized to move the same along the subgrade, comprising a part connected to the rear of the conveyor frame and fixed against translatory movement relative thereto, and track means on the trailing vehicle engaged with said conveyor part to constrain the same to move transversely of the subgrade during swinging movement of the conveyor about its axis.

3. In apparatus for placing concrete upon a. subgradei a leading vehicle adapted for travel along the subgrade; a concrete spreading vehicle adaptedfor travel along the subgrade in spaced trailing relation to the leadingvehicle, and having an elongated trough to transversely span the subgrade; an elongated conveyor having a frame providing a link of fixed length extending lengthwise between the vehicles, for conducting concrete rearwar'dly from the leading vehicle and for discharging such concrete into said trough; conveyor supporting means pivotally connect ing the front of the conveyor frame to the leading vehicle for swinging motion of the conveyor about an upright axis fixed with respect to the leading vehicle, so that the rear portion of the conveyor can swing crosswise of the subgrade, from end to end of the trough, to thus effect discharge of concrete into the trough all along the length thereof; means connecting the rear portion of the conveyor frame with the trough so as to assure discharge of concrete from the conveyor into the trough regardless of the position to which the conveyor is swung relative to the trailing vehicle, comprising a part on the conveyor frame fixed against relative movement lengthwise thereof and which moves back and forth with the conveyor, and means on the trailing vehicle engaging said part to constrain the same to movement substantially lengthwise of the trough as the conveyor swings back and forth across the subgrade; and power means on one of said vehicles operatively connected with the conveyor frame to impart back and forth swinging'mo'tion thereto, said power means cooperating with the link provided by the conveyor frame and said means connecting it with the leading and trailing vehicles to cause the trailing vehicle to be pulled toward 7 the leading vehicle by the conveyor frame when the conveyor isswung in one direction at times when the leading vehicle is held against movement, and to cause the leading vehicle to be pushed away from the trailing vehicle by the conveyor frame when'the conveyor is swung in the opposite direction at times when the trailing vehicle is held against movement.

4. In apparatus for placing concrete upon a subgrade: spacedapa'rt leading and trailing vehicles adapted to span and travel along the subgrade; means on the rear of the.

trailing vehicle defining an elongated. concrete spreading trough to transversely span the subgrade; and elongated conveyor having a frame providing 'a link of fixed length 12 extending lengthwise between the vehicles, and having a delivery end at its rear from which concrete discharges into said trough; means supporting the front portion of the conveyor frame on the leading vehicle for pivotal motion of the conveyor about an upright axis fixed with respect to the leading vehicle and near one transverse end of the leading vehicle, to provide for back and forth swinging motion of the conveyor between a first position at which the conveyor is lengthwise aligned with the subgrade and closely adjacent to one side thereof, and a second position at which the conveyor extends substantially diagonally across the subgrade; power means on one of said vehicles operatively connected with the conveyor frame to impart back and forth swinging motion to the conveyor; and means connecting the rear portion of the conveyor frame with the trailing vehicle so that the conveyor receives support therefrom, comprising a track structure on the trailing vehicle extending lengthwise of the trough thereon, and track engaging follower means on the conveyor frame movable back and forth therewith but fixed against translatory movement relative to the conveyor.

5. Apparatus for spreading concrete upon a subgrade, comprising: a leading vehicle adapted for travel along the subgrade; a second vehicle adapted to trail the leading vehicle, said trailing vehicle having a transversely elongated chassis which is adapted to span the subgrade, and supporting wheels on the opposite ends of the chassis; an elongated conveyor extending lengthwise between the leading and trailing vehicles, for conducting concrete rearwardly from the leading vehicle, said conveyor having a supporting frame providing a link of fixed length; means pivotally supporting the front of the conveyor frame on the leading vehicle for swinging movement about a fixed vertical axis; means connecting a rear portion of the conveyor frame with the trailing vehicle, comprising a dolly movably carried by the chassis of the trailing vehicle and constrained to travel from side to side of the trailing vehicle, along the length of its chassis, and means supportingly connecting the conveyor frame with the dolly for turning movement relative thereto about a vertical axis fixed with respect to the dolly and the conveyor frame, whereby the dolly is moved from side to side of the trailing vehicle in consequence of swinging of the conveyor, and the vehicles can be moved relatively'to one another through the link provided by the conveyor frame in consequence of said side to side movement of the dolly; and a feed hopper carried by the leading vehicle and positioned to discharge onto the forward end portion of the conveyor, into which concrete may be dumped from a transit truck or the like.

6 The apparatus of claim 5, further characterized by means on the rear of the trailing vehicle defining a transversely elongated strike oif long enough to span the subgrade, said strike olf being positioned to act upon concrete discharged onto the subgrade from the rear of the conveyor to aid in leveling the concrete upon the subgrade. r 7. The apparatus of claim 6, further characterized by means mounted on the trailing vehicle and extending transversely thereacrossat a level spaced a predetermined distance below the strike off to lift up reinforcing members laid in the subgrade ahead of the trailing vehicle and to support the same at a predetermined distance beneath the surface of concrete deposited upon the subgrade while the concrete flows thereonto.

8. Apparatus for spreading concrete upon a subgrade of predetermined width, comprising: a rigid elongated concrete distributing structure which is open at its top and bottom and has a length to span the subgrade. upon which concrete is to be spread; means on said distributing structure to support the same for travel along the length of the subgrade; means on the. rear of the distributing structure providing a strike off which extends entirely across the length of said structure and has a lower edge 05, one forwardly and the other rearwardly of the distributing structure, for picking up reinforcing matting laid upon the subgrade ahead of the distributing structure, in consequence of travel thereof along the subgrade, and for supporting said matting beneath the distributing structure at said elevation beneath the lower edge of the strike off while concrete is being placed upon the subgrade by the distributing structure, the rear one of said elongated members being located close to the strike 01? and comprising a substantially fiat bar having an upper surface which slopes gently downwardly toward the leading edge of the bar so as to knife cleanly through concrete deposited on the subgrade from the distributing structure and to enable said rear member to slide smoothly under reinforcing matting ahead of it.

9. The apparatus of claim 8, further characterized by: means on the distributing structure supporting said elongated transverse members for up and down movement toward and from inoperative positions at Which said members are disposed at levels above the strike off; and means on the distributing structure for effecting such up and down movement of said members.

v 10. The apparatus of claim 8, further characterized by means on the distributing structure acting upon said elongated transverse members through the supporting means therefor to maintain said members under tension.

References Cited by the Examiner UNITED STATES PATENTS 1,193,124 8/16 Copley 198-118 X 1,504,960 8/24 Llewellyn 198-125 1,539,145 5/25 Robb 94-46 X 1,540,901 6/25 Robb 94-46 1,731,231 10/29 Chenoweth 94-44 1,750,896 3/ 30 Lichtenberg 94-44 X 1,755,653 4/30 Koehring 94-46 1,878,278 9/32 Jaeger 94-44 1,895,991 1/33 Heltzel 94-46 X 1,977,850 10/ 34 Heltzel 94-39 2,123,989 7/38 Day 94-46 2,649,185 8/53 Lichtenberg 94-46 X 2,781,890 2/57 Mercier 198-124 3,022,713 2/62 Friberg 94-8 X 3,107,592 10/63 Mengel 94-46 BENJAMIN BENDE IT, Primary Examiner.

JACOB L. NACKENOFF, Examiner. 

2. IN APPARATUS FOR PLACING CONCRETE UPON A SUBGRADE: SPACED APART LEADING AND TRAILING VEHICLES ADAPTED TO SPAN AND TRAVEL ALONG THE SUBGRADE; AN ELONGATED CONVEYOR HAVING A FRAME EXTENDING LENGTHWISE BETWEEN SAID VEHICLES, FOR CONDUCTING CONCRETE REARWARDLY FROM THE FIRST VEHICLE AND DISCHARGING IT ONTO THE SUBGRADE AT A LOCATION ADJACENT TO THE TRAILING VEHICLE, SAID FRAME PROVIDING A LINK OF FIXED LENGTH; MEANS SUPPORTINGLY CONNECTING THE FRONT PORTION OF THE CONVEYOR FRAME TO THE LEADING VEHICLE FOR PIVOTAL MOTION OF THE CONVEYOR ABOUT AN UPRIGHT AXIS FIXED WITH RESPECT TO THE LEADING VEHICLE, SO AS TO PROVIDE FOR SWINGING THE CONVEYOR BACK AND FORTH ACROSS THE SUBGRADE, TOWARD AND FROM A POSITION AT WHICH THE CONVEYOR IS IN ENDWISE ALIGNMENT WITH THE SUBGRADE; MEANS ON THE TRAILING VEHICLE SUPPORTING THE REAR PORTION OF THE CONVEYOR FRAME FOR BACK AND FORTH SWINGING MOVEMENT OF THE CONVEYOR RELATIVE TO THE TRAILING VEHICLE; POWER MEANS ON ONE OF SAID VEHICLES OPERATIVELY CONNECTED WITH THE CONVEYOR FRAME FOR IMPARTING BACK AND FORTH SWINGING MOVEMENT THERETO; AND MEANS COOPERATING WITH THE LINK PROVIDED BY THE CONVEYOR FRAME TO PROVIDE FOR TRANSLATION OF FORCES WHICH SAID POWER MEANS IMPOSES THEREON TO SWING THE CONVEYOR BACK AND FORTH ACROSS THE SUBGRADE INTO FORCES ON SAID VEHICLES THAT CAN BE UTILIZED TO MOVE THE SAME ALONG THE SUBGRADE, COMPRISING A PART CONNECTED TO THE REAR OF THE CONVEYOR FRAME AND FIXED AGAINST TRANSLATORY MOVEMENT RELATIVE THERETO, AND TRACK MEANS ON THE TRAILING VEHICLE ENGAGED WITH SAID CONVEYOR PART TO CONSTRAIN THE SAME TO MOVE TRANSVERSELY OF THE SUBGRADE DURING SWINGING MOVEMENT OF THE CONVEYOR ABOUT ITS AXIS. 